Chapter 2 Diversity in the Living World Revision Notes Class 6 Science
Diversity in the Living World Chapter Notes Class 6
- Introduction
- Diversity in Plants
- Diversity in Animals
- Biodiversity
- How to group Plants?
- How to group Animals?
- Plants and Animals in different Surroundings
- Adaptation
- Habitat
- Protecting Biodiversity
Introduction
A nature walk is an exciting and educational experience where students get the chance to explore and observe the beauty and diversity of plants and animals in their natural environment. Led by experts like Dr. Raghu, a scientist, and Maniram chacha, an elderly local with deep knowledge of nature, students can learn about the variety of species, their unique features, and the importance of respecting all living creatures. This activity encourages curiosity and helps students develop a deeper connection with the natural world around them.
- Diversity means the variety and differences found among living things in a particular area.
When we talk about the diversity in plants and animals around us, we are looking at how many different types of plants and animals live in a specific place and how they are different from each other.
Diversity in Plants
Plants can be very different from one another in several ways, such as their size, shape, and the way they grow. Here are some ways plants can differ:
1. Measuring the height of a plant accurately:
- Tall: Some plants, like mango trees, grow very tall and have a strong, thick trunk.
- Short: Other plants, like rose bushes, are much shorter and closer to the ground.
2. What does the stem of this plant look like?
- Hard: Plants like the banyan tree have hard, woody stems that provide strong support.
- Soft: Smaller plants like mint have soft, green stems that are flexible and not as strong as woody stems.
3. Some common shapes of leaves that you can see in different plants:
- Shape: Leaves come in different shapes; for example, banana leaves are broad and large, helping the plant capture more sunlight.
- Arrangement: Leaves can be arranged in different patterns on the stem. For instance, neem leaves grow opposite each other on the branch.
4. Different colours in the flowers:
- Colour: Flowers have various colours, like the bright red of a hibiscus flower, which can attract pollinators.
- Scent: Some flowers, like jasmine, have a strong, pleasant scent that also helps attract insects for pollination.
Diversity in Animals
Animals also show a lot of diversity. They can be different in their size, shape, and the way they move. Here are some ways animals can differ:
1. Where does animals usually live?
- This describes the habitat or environment where the animal lives.
- Some animals live on land, like in forests or fields, while others might live in water, like rivers or ponds.
- Some animals even live in the air, like birds that build nests in trees.
2. What kind of food does this animal need to stay healthy?
- This tells us about the type of food the animal eats.
- Different animals have different diets.
- Some animals eat plants, like grass or leaves, while others might eat meat or insects.
- There are also animals that eat a mix of both plants and meat.
3. How does this animals move?
- Walking: Animals like cats and dogs use their legs to walk.
- Flying: Birds like eagles and sparrows use their wings to fly.
- Swimming: Fish like goldfish and sharks use their fins to swim.
- Crawling: Reptiles like snakes and lizards crawl using their body muscles.
Biodiversity
- Biodiversity refers to the variety of different plants, animals, and other living organisms found in a particular region or environment.
For Example, trees offer food and shelter to certain birds and animals, while animals aid in seed dispersal by consuming fruits, and so on.
How to Group Plants and Animals?
Can you find a group of plants or animals that have something in common? For example, do any of them have similar colours, shapes, or sizes?
Grouping plants and animals simplifies the study and understanding of their vast diversity, making it easier to identify, compare, and classify them. It helps in understanding evolutionary relationships and ecological roles, ensuring effective communication and research among scientists.
How to group Plants?
Grouping plants helps in understanding their characteristics and categorizing them based on common features.
1. Based on Height:
- Trees are plants that grow very tall and have hard, thick, brown, and woody stems. Their branches usually start higher up on the stem, away from the ground. An example of a tree is the mango tree.
- Shrubs are plants that are not as tall as trees. They have many brown woody stems that start branching close to the ground. These stems are hard but not as thick as the stems of trees. An example of a shrub is the rose plant.
- Herbs are typically small plants with soft and green stems. An example of an herb is the tomato plant.
- Climbers are plants with weak stems that need support to climb and grow, while Creepers are plants that grow by creeping along the ground.
2. Based on Stems:
- Hard Stem: In some plants, the stem is very hard and tough. This is usually found in trees and shrubs, where the stem is strong and woody. It helps the plant stand firm and survive in different weather conditions.
- Soft Stem: Some plants have soft and green stems. These stems are not as strong as hard stems and are usually found in smaller plants like flowers, herbs, and vegetables.
3. Based on Branches:
- Close to the Ground: Branches that start growing near the base of the stem, like in shrubs.
- Higher up on the Stem: Branches that begin higher up on the stem, away from the ground, like in trees.
4. Based on Leaves:
Leaves can have different shapes and sizes. For example, the broad leaves of a mango tree are different from the thin leaves of grass. Leaves have veins that provide support and transport water and nutrients. The pattern of these veins is called venation.
- Reticulate Venation: Veins form a network, common in dicot plants like hibiscus and peepal.
- Parallel Venation: Veins run parallel to each other, common in monocot plants like grass and wheat.
5. Based on Roots:
Roots are the parts of a plant that grow underground and help the plant stay anchored in the soil.
There are two main types of roots:
- Taproots: These roots have one main root that grows straight down with smaller side roots branching off from it. An example of a taproot is the mustard plant or hibiscus.
- Fibrous Roots: These roots are a bunch of thin, similar-sized roots that spread out from the base of the stem. An example of fibrous roots is the grass plant.
6. Based on Seeds:
Seeds are the small parts of a plant that can grow into a new plant.
There are two main types of seeds based on the number of cotyledons (the first leaves that appear from the seed):
- Dicotyledons (Dicots): These seeds have two cotyledons, which can be split into two parts. An example of a dicot seed is a chickpea. Plants with dicot seeds usually have reticulate venation (a net-like pattern of veins on the leaves) and a taproot system.
- Monocotyledons (Monocots): These seeds have a single, thin cotyledon. An example of a monocot seed is maize (corn). Plants with monocot seeds typically have parallel venation (veins running parallel on the leaves) and a fibrous root system.
How to group Animals?
Grouping animals helps in studying their behaviour, characteristics, and features they share.
Based on Movement:
- Flying: Animals that use wings to move through the air, like birds.
- Running/Walking: Animals that use legs to run or walk on the ground, like dogs and horses.
- Crawling: Animals that move by crawling on their bodies, like snakes.
- Hopping/Jumping: Animals that hop or jump using their legs, like frogs and rabbits.
These categories help us understand and organize animals based on their movement and the body parts they use to move.
Plants and Animals in different Surroundings
Adaptations are special features or behaviours that help plants and animals survive in their environments.
1. In the Desert
- Plant: Cactus plants with thick and fleshy stems that store water to survive the hot, dry conditions.
- Animal: Camels with long legs, wide hooves, and the ability to store food in their humps, helping them walk on sand and survive without water for days.
2. On Mountains
- Plant: Deodar trees with a conical shape and sloping branches that allow snow to slide off easily, helping them survive in cold, snowy regions.
- Animal: Mountain goats that are adapted to the cold and rocky terrain, allowing them to move easily on steep slopes.
3. In the Ocean
- Plant: Seaweed and other marine plants that thrive underwater.
- Animals: Fish with streamlined bodies and fins that help them move easily in water.
4. In the Forest
- Plant: Various trees like the bamboo, which grow tall and provide shelter to many animals.
- Animal: Lions, which live and hunt in dense forests.
Rhododendron
- Rhododendrons are plants that produce beautiful bright flowers. They can be found in different regions and may look different depending on where they grow.
- For example, in the Shola forests of Nilgiris, rhododendrons are shorter with smaller leaves, which helps them survive the strong winds on mountain tops. In contrast, in the mountains of Sikkim, rhododendrons are taller. These differences help the plant adapt to the specific conditions of each region.
Adaptations
- Adaptations are special features or behaviours that help plants and animals survive in their specific surroundings.
These adaptations make it easier for them to find food, stay safe, and live in their environment.
For example:
- Camels have long legs and humps that store fat, helping them survive in the hot desert.
- Fish have fins and gills, allowing them to swim and breathe underwater.
- Cacti have thick stems to store water and spines instead of leaves to reduce water loss in the desert.
Adaptations are like nature’s way of making sure every living thing has what it needs to live where it does.
Habitats
- A habitat is the natural environment where a plant or animal lives, providing the necessary conditions for survival, such as food, water, shelter, and space.
Different plants and animals are adapted to live in specific habitats that suit their needs.
Types of Habitats
1. Terrestrial (Land-based) Habitats:- Forests: Dense areas with a variety of trees and wildlife. Examples include tropical rainforests with species like tigers, monkeys, and a wide variety of trees and plants.
- Deserts: Dry areas with sparse vegetation and specialized animals. Examples include cacti, camels, and snakes adapted to conserve water and withstand high temperatures.
- Grasslands: Open areas with grasses and few trees. Examples include zebras, lions, and grasses that can survive with less water.
- Freshwater Habitats: It includes Rivers, lakes, and ponds. Examples include fish like trout, frogs, and aquatic plants like water lilies.
- Marine Habitats: It includes oceans and seas. Examples include whales, sharks, coral reefs, and seaweed.
- Amphibians: These animals can live both on land and in water. Examples include frogs, salamanders, and toads, which have adaptations for both environments.
Protecting Biodiversity
- To protect biodiversity, we need to take care of our environment. This includes not polluting our surroundings, conserving natural habitats, and using resources sustainably. By protecting biodiversity, we ensure that all living things can thrive.
Examples: Planting trees, reducing plastic use, and supporting wildlife conservation projects.